Originally posted by AThousandYoung
My understanding is that this is not an idea that is taken seriously by anthropologists.
Cro-Magnon had better technology and outcompeted Neandertal I think. For example, Neandertal had no javelins. Their diet was less varied too...pretty much all meat.
They were also less mobile. Much stronger, but less able to run and walk easily.
As an archaeologist...
There is some evidence (albeit arguable) to suggest that Neanderthals or their predecessors did
possess projectile spear technology (Boxgrove c.500kbp, Schoningen c.400kbp, Clacton c.400kbp, Lehringen c.125kbp). Latest thinking suggest that Neanderthal diet may not
have been significantly different from early modern man (http://www.nhm.ac.uk/nature-online/life/human-origins/neanderthals-diets/index.html).
It is often suggested that Neanderthals did not adapt so rapidly as early moderns, at least, not until early moderns were sharing their living space, but recent work has often argued against this as well.
Skeletal evidence does suggest that moderns would have been better suited to rapid ambulation, but this is based on very small samples and may be fallacious also.
Currently it is very difficult to find evidence to show any significant advantage for moderns over Neanderthals.
Still, the best guess remains competitive exclusion, as it would only take a very slight advantage to see them squeezed out of living space by moderns over the timespans involved.
Could equally be something else though - naked hostility, disease, environment etc. More evidence required!